Create a new Layer at the top and name it Collisions
import it into Construct as a TileMap
Replace the default TileMap image.
In the TileMap Properties
Set the Tile Size to 64 x 64
Disable Initially Visible
Before you paint the level.
Double-click on each individual tile and then:
Right-click on each individual tile in the map.
Use the TileMap and block out the collision layer as shown
Once you have painted the TileMap
move it between the Foreground and Background Layers
This allows us to see both the Level Design and the Collisions
Lastly, add the Solid behaviour to the TileMap